Method, system and network element for data transmission using a transition mechanism

ABSTRACT

A data transmission from a first node, such as a user equipment, to a second node, such as an application server or IMS, via a communication network using different types of communication protocols, such as a 3GPP communication network using IPv6 and IPv4, may be controlled by means of a transition mechanism, such as ISATAP. The transition mechanism may be located in the communication network, for example, in a gateway node like a GGSN, which typically acts as a transition mechanism proxy. A data transmission from the first node is commonly forwarded by the network node to the second node wherein the transition mechanism functionality is performed in the network node transparently for the first node.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present specification relates generally to a method and/or asystem and/or a network node commonly usable for controlling a datatransmission in a communication network. The present specification isalso generally related to a data transmission control in a communicationnetwork which typically uses different types of transmission mechanismsand/or protocols, such as, for example, IPv4 and IPv6, particularly in acoexistence phase during a transition from one transmission mechanism toanother, usually new, transmission mechanism in the communicationnetwork.

[0003] 2. Description of the Related Art

[0004] In the last few years, an increasing extension of data andcommunication networks, in other words, of wire based networks, such as,but not limited to, the Integrated Services Digital Network (ISDN),and/or wireless networks, such as, but not limited to, the CDMA2000(code division multiple access) system, Universal MobileTelecommunications System (UMTS), the General Packet Radio System(GPRS), and/or other wireless communication systems, such as, but notlimited to, the Wireless Local Area Network (WLAN), took place all overthe world. Various organizations, such as the 3^(rd) GenerationPartnership Project (3GPP), the International Telecommunication Union(ITU), 3^(rd) Generation Partnership Project 2 (3GPP2), InternetEngineering Task Force (IETF), and the like are working onstandardization for such networks.

[0005] In general, the system structure of a communication network issuch that a user equipment, such as a mobile station, a mobile phone, afixed phone, a personal computer (PC), a laptop, a personal digitalassistant (PDA) or the like, is connected, commonly via transceivers andinterfaces such as an air interface, a wired interface or the like, toan access network subsystem. The access network subsystem normallycontrols the communication connection to and/or from the user equipmentand is usually connected via an interface to a corresponding core and/orbackbone network subsystem. The core, or backbone, network subsystemtypically switches the data transmitted via the communication connectionto a destination, such as another user equipment, a service provider(server/proxy), and/or another communication network. The core networksubsystem may be connected to a plurality of access network subsystems.The respective network structure may vary, as known to those skilled inthe art, and may be defined in respective specifications, for example,for UMTS, GSM and the like.

[0006] Generally, for properly establishing and/or handling acommunication connection between network elements such as, for example,the user equipment and another user terminal a database a server, etc.one or more intermediate network elements, such as, but not limited to,support nodes and/or service nodes are generally involved. Data, such asvoice, multimedia, control signaling data and the like, are transmitted,for example, by means of a packet based data transmission. One examplefor a utilized packet based data transmission protocol is the InternetProtocol (IP). For this protocol type, there are currently availableseveral versions, for example, IPv4, and the like, which are commonlyknown. However, due to changing requirements and/or load conditions inthe networks, more sophisticated versions have been developed, such asIPv6.

[0007] For example, with regard to the above mentioned IPv4 and IPv6,the IPv4 address space is typically being rapidly exhausted as new nodesand/or networks are added to the Internet routing structure. One greatbenefit of IPv6 is that it generally provides a considerably largeraddress space. Although addressing capabilities of IPv4 have, in manyinstances, been successfully extended by introducing, for example,private addressing, temporary global addresses and/or addresstranslators, it may become the case that, with the current growth rateof the Internet, at least in terms of number of hosts connected to itand in terms of adoption of new services, the number of unique globallyroutable addresses being available in the IPv4 addressing domain may notremain sufficient for the future needs. Thus, one main motivation forIPv6 deployment results from the general preference for globalreachability of Internet hosts. Furthermore, IPv6 also commonly offersan enhanced security level and/or mobility support.

[0008] Of course, when network operators change the existing IPv4network environment to IPv6, there will typically be a transition periodwhen IPv4 hosts coexist with IPv6 hosts. Taking this into consideration,there have been developed several transition mechanisms which generallyaim to maintain interoperability during this transition period betweenIPv4 and IPv6 parts. These mechanisms may generally be classified intothree main groups: Dual Stack, Tunneling and Protocol Translation. ADual Stack node commonly implements both IPv4 and IPv6 protocol stacks,normally allowing connection to both IPv4 and IPv6 networks. Tunnelingis usually a forwarding technique in which a packet is typicallyencapsulated into another type of packet, for example, IPv6 datagramsmay be encapsulated within IPv4 packets and may be decapsulated at acorresponding receiving node. Thus, this technique generally provides away to utilize an existing IPv4 routing infrastructure to carry IPv6traffic, or vice versa. Tunneling commonly requires dual stackfunctionality in both encapsulating and decapsulating nodes. Finally,Protocol Translators are normally required when two communicating nodesare not sharing the same version of IP.

[0009] In “Intra-Site Automatic Tunnel Addressing Protocol (ISATAP)” byF. Templin et al., there is defined one example of a specific type ofsuch a transition mechanism for providing IPv6 connectivity within anIPv4 network. Another example for a transition mechanism is disclosed,for example, in RFC (Request for Comments) 3056, “Connection of IPv6Domains via IPv4 Clouds” by B. Carpenter et al.

[0010] As shown in FIG. 5, in the case of ISATAP, ISATAP nodes typicallyhave special IPv6 addresses, usually with a special ISATAP formatinterface identifier, which normally embeds an IPv4 address. The ISATAPaddress format generally includes two portions, for example, a networkportion (IPv6 prefix) and a host portion. ISATAP nodes are commonlyassigned a normal IPv6 prefix 11, for example, of 64-bit size, which maybe, for example, link-local, site-local or global scope, and thespecific ISATAP format interface identifier 12, 13 of, for example,32+32 bit=64-bit size. The interface identifier is commonly constructedby using a “modified EUI-64” format according to the IEEE EUI-64standard, usually by appending an IPv4 address 13, which is normallyassigned to the node, to a 32-bit string ‘00-00-5E-FE’ 12 whichtypically includes an organizationally-unique identifier (OUI) and/or arespective type field. For the IPv4 address, either public or privateIPv4 addresses may be used.

[0011] In FIG. 6, an example of an implementation of a transitionmechanism, such as ISATAP, in a communication network, for example, a3GPP based communication network, is shown.

[0012] According to FIG. 6, reference character 5 denotes a userequipment (UE) which is commonly a dual stack device implementing bothIPv4 and IPv6 stacks. Reference character 21 denotes a Gateway GPRSSupport Node (GGSN) representing a control network element of, forexample, a 2G/3G mobile network 30. As commonly known, the 2G/3G mobilenetwork typically further includes access network subsystem elementsand/or core network subsystem elements, not shown, for establishingand/or controlling a communication connection of the UE 5. Referencecharacter 100 denotes an IPv4 based operator network. Referencecharacter 40 denotes an operator services portion of the operatornetwork which typically includes one or more IPv6 based applicationservers, although, to enhance clarity, only one thereof is shown,providing IPv6 based services. Reference character 50 denotes an IPMultimedia Subsystem generally including, for example, a Proxy CallState Control Function (P-CSCF), an Interrogating Call State ControlFunction (I-CSCF), and/or a Serving Call State Control Function(S-CSCF). Reference character 60 denotes an edge and/or border router.The above mentioned elements are known to a person skilled in the art sothat a detailed description thereof may be omitted.

[0013] According to ISATAP, the site's IPv4 infrastructure 100 isnormally treated as a link layer for IPv6 communications, usually usingautomatic IPv6-in-IPv4 tunneling. This typically enables an incrementaldeployment of IPv6 infrastructure within the IPv4 sites with no scalingissues at border gateways. Moreover, no special IPv4 services within thesite, for example, multicast, are normally required. In addition, ISATAPgenerally supports both manual address configuration and statelessaddress autoconfiguration, and it is usually compatible with othertransition mechanisms, for example, the 6 to 4 tunneling according toRFC 3056.

[0014] As also shown in FIG. 6, ISATAP nodes are commonly dual stackterminals 5 which are often capable of automatically tunneling datapackets to the IPv6 next-hop address through the IPv4 infrastructure.This means that, at least for the application of the ISATAP mechanism ina 3GPP network, the ISATAP functionality, in other words, packetencapsulation/decapsulation, etc., typically resides in the UE 5. Thus,in the example shown in FIG. 6, the IPv6-in-IPv4 tunneling is generallyperformed in the UE 5. Packets are commonly sent via the 2G/3G mobilenetwork's GGSN 21 by means of, for example, IPv4 PDP context connection6, and the corresponding ISATAP links 46 and 56 normally extend from theUE 5 to the respective IPv6 service located in portions 40 and/or 50.

[0015] However, the usage of a transition mechanism, such as ISATAP, mayincrease the complexity of the communication system and, for example,the costs of a corresponding user equipment. When deploying, forexample, ISATAP in a 3GPP cellular operator network, the UEs preferablyimplements all the ISATAP node functionality in order to allow tunnelingof IPv6 packets over the IPv4 network. In other words,encapsulation/decapsulation is typically performed in the UE. Thisgenerally involves a huge increase in the complexity and/or costs of theUEs, and different vendors commonly have to implement ISATAP in theirterminals in order to enable IPv6 connections within an IPv4 operatornetwork. Therefore, the deployment of transition mechanism, and thusalso of more sophisticated communication protocols, or the like, in anexisting network structure, may become complicated. Further, there isthe possibility that the migration to the more sophisticatedcommunication technique, for example, the migration from IPv4 to IPv6,may be decelerated, especially since a demand of IPv6 services by thevast majority of users is typically reduced because, presumably, onlyhigh-end, and expensive, terminals are usually capable of accessing IPv6services.

SUMMARY OF THE INVENTION

[0016] Thus, it is generally desirable to provide an improved mechanismfor controlling data transmission, usually in connection with atransition mechanism which allows the above limitations to be overcome.

[0017] This may, for example, be achieved by the measures recited in theappended claims.

[0018] According to certain embodiments of the present invention, thereis provided, for example, a method of controlling a data transmission,generally from a first node to a second node, via a communicationnetwork wherein the first node is typically connected to thecommunication network by means of, for example, a communication protocolof a first type and wherein the communication network commonly uses, atleast in part, a communication protocol of a second type for forwardingthe data transmission from the first node to the second node. The methodgenerally includes the steps of activating a communication connection,typically based on the communication protocol of the first type from thefirst node to a network node of the communication network, allocating afirst connection information part normally including an address relatedto the communication protocol of the first type to the communicationconnection of the first node, allocating, usually based on a transitionmechanism used by the communication network, a second connectioninformation part commonly including an address related to thecommunication protocol of the second type to the communicationconnection of the first node, and storing, typically by the networknode, the first connection information part and/or the second connectioninformation part in a register, wherein the second connectioninformation part is normally associated with the first connectioninformation part in a common entry in the register.

[0019] Furthermore, according to certain embodiments of the presentinvention, there is provided, for example, a system for controlling adata transmission from a first node to a second node, usually via acommunication network. The first node is generally connected to thecommunication network by means of a communication protocol of a firsttype and the communication network typically uses, at least in part, acommunication protocol of a second type for forwarding the datatransmission from the first node to the second node. The system commonlyincludes means for activating a communication connection, often based onthe communication protocol of the first type, usually between the firstnode and a network node of the communication network, means forallocating a first connection information part normally including anaddress related to, for example, the communication protocol of the firsttype to the communication connection of the first node, means forallocating, generally on the basis of a transition mechanism that may beused by the communication network, a second connection information partcommonly including an address related to the communication protocol ofthe second type to the communication connection of the first node,and/or means for associating the second connection information part withthe first connection information part and/or for storing the associatedfirst and second connection information parts, typically in a register.

[0020] Moreover, according to certain embodiments, there may beprovided, for example, a network node of a communication network, thenetwork node commonly being usable for controlling a data transmissionfrom a first node to a second node, usually via the communicationnetwork, wherein the first node is normally connected to the networknode by means of, for example, a communication protocol of a first typeand wherein the communication network generally uses, at least in part,a communication protocol of a second type, usually for forwarding thedata transmission from the first node to the second node. The networknode typically includes means for activating a communication connection,usually based on the communication protocol of the first type betweenthe first node and the network node, means for allocating a firstconnection information part commonly including an address related to thecommunication protocol of the first type to the communication connectionof the first node, means for allocating, generally on the basis of atransition mechanism used by the communication network, a secondconnection information part often including an address related to thecommunication protocol of the second type to the communicationconnection of the first node, and/or means for associating the secondconnection information part with the first connection information partand/or for storing the associated first and second connectioninformation parts, commonly in a register.

[0021] Certain other embodiments may include one or more of thefollowing features:

[0022] for the activation of the communication connection, an activationrequest may be sent from the first node to the network node, theactivation request typically including at least one of an indication fora dynamic addressing and an indication of an address type for thecommunication protocol of the first type;

[0023] for allocating the first connection information part commonlyincluding an address related to the communication protocol of the firsttype to the communication connection of the first node, the addressrelated to the communication protocol of the first type may be allocatedby the network element;

[0024] for allocating the first connection information part generallyincluding an address related to the communication protocol of the firsttype to the communication connection of the first node, the addressrelated to the communication protocol of the first type may be requestedfrom an external address allocation element, normally contacted by thenetwork element;

[0025] for allocating the second connection information part usuallyincluding an address related to the communication protocol of the secondtype to the communication connection of the first node, the addressrelated to the communication protocol of the second type may beallocated by the network element, typically from an internal pool ofaddresses;

[0026] for allocating the second connection information part commonlyincluding an address related to the communication protocol of the secondtype to the communication connection of the first node, the addressrelated to the communication protocol of the second type may berequested from an external address allocation element, generallycontacted by the network element;

[0027] the network element may store the first connection informationpart and/or the second connection information part associated with eachother by, for example, an entry in a table portion that is typicallyrelated to the communication connection of first node, wherein thesecond connection information part may be stored in a specific tablefield of the table portion;

[0028] the data transmission based on the communication protocol of thefirst type may be tunneled between the first node and the second node,commonly via the network node, generally by means of a connection basedon the communication protocol of the second type;

[0029] the data transmission may be a packet based data transmission,the communication protocol of the first type may be one type of anInternet protocol, according to certain embodiments, an IPv6 basedprotocol, and the communication protocol of the second type may beanother type of an Internet protocol, according to certain embodiments,an IPv4 based protocol;

[0030] the communication connection between the first node and thenetwork node may be based on a packet based data transmission protocolcontext, for example, on a Packet Data Protocol context;

[0031] the transition mechanism used by the communication network may bean automatic tunneling mechanism which typically uses, for example, theIntra-Site Automatic Tunnel Addressing Protocol;

[0032] the network node may be a gateway node of the communicationnetwork such as, for example, a Gateway GPRS Support Node.

[0033] By virtue of certain embodiments of the present invention, thefollowing advantages may be achieved:

[0034] It is generally possible for the complete functionality of thetransition mechanism to be centralized in, for example, a network nodeof the communication network and commonly does not need to be performedin the user equipment. For example, the ISATAP functionality may beperformed by a GGSN instead of the UE and/or IPv6 tunneling over an IPv4operator network may be achieved by performingencapsulation/decapsulation of packets in the operator network. Hence,by providing a transition mechanism proxy in the communication network,for example, an ISATAP proxy for the 3GPP network, it is generallypossible that the GGSN implements all, or at least a major portion, ofthe ISATAP functionality on behalf of the UE, thus typically avoiding anunnecessary increase in the terminal's (UE's) complexity and/or costs.

[0035] Certain embodiments of the present invention may be easilyimplemented by means of, for example, modifications in existing networknode structures, such as, but not limited to, the GGSN. On the otherhand, no additional configuration is normally needed in the terminals,such as, but not limited to, the UE. According to certain embodiments,the proposed solution may be implemented by means of softwaremodifications.

[0036] The transition mechanism, for example, ISATAP, functionalityemployed by the network node is often transparent to the UE whichgenerally allows the usage of terminals not specifically prepared forthe transition mechanism. In particular, it is not commonly requiredthat the UE be a dual stack UE. In other words, it is typicallysufficient when the UE supports, for example, the access to IPv6services, such as IP Multimedia Subsystem (IMS) or the like. However,certain embodiments of the present invention are also generallyapplicable in connection with such dual stack terminals. Thus, almostany terminal is normally able to make use of IPv6 services, whichusually results in increasing the demand of new end-to-end servicesand/or paving the way for, for example, IPv6 migration.

[0037] The above and still further objects, features and advantages ofcertain embodiments of the present invention will become more apparentupon referring to the description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] For an enhanced understanding of certain embodiments of thepresent invention, reference may be made to the accompanying drawings,wherein:

[0039]FIG. 1 shows an example of an implementation of a transitionmechanism in a communication network according to certain embodiments ofthe present invention;

[0040]FIG. 2 shows an example of a packet based data transmissionprotocol address information element;

[0041]FIG. 3 shows an example of a communication connection activationprocedure according to certain embodiments of the present invention;

[0042]FIG. 4 shows an example of a communication connection activationprocedure according to certain other embodiments of the presentinvention;

[0043]FIG. 5 shows an illustration of an exemplary ISATAP addressformat; and

[0044]FIG. 6 shows an example of an implementation of a transitionmechanism in a communication network.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

[0045] According to certain embodiments of the present invention, a datatransmission from a first node, such as, but not limited to, asubscriber's terminal node or user equipment UE, to a second node, suchas, but not limited to, an application server or a multimedia subsystemlike, for example, IMS, via a communication network, such as, but notlimited to, a 3GPP communication network, is typically controlled bymeans of a transition mechanism. In other words, the communicationnetwork generally implements a communication protocol of a first type,such as IPv6, and, at least in part, a communication protocol of asecond type, such as IPv4, in the operator network. The transitionmechanism is commonly located in the communication network, for example,in a gateway node like a GGSN. Hence, according to certain embodiments,the network node normally acts as a transition mechanism proxy for thedata transmission. Thus, a data transmission from the first node istypically forwarded, and/or tunneled, by the network node to the secondnode, wherein the transition mechanism functionality is generallyperformed in the network node transparently for the first node.

[0046] According to certain embodiments, the term communication networkis commonly not only a type of one single network but also typically anetwork type which may be split into other network types, such as anoperator's network, a radio access network, etc.

[0047] The user equipment (UE) may be a terminal apparatus of adifferent type. For example, the UE may be a mobile or fixed phone, apersonal computer, a server, a mobile laptop computer, a personaldigital assistant (PDA) or the like. Irrespective of its specific type,the UE may include several means which are highly preferable for itscommunication functionality. Such means may include, for example, aprocessor unit for executing instructions and/or processing data for thecommunication connection, for example, transmission content and/orsignaling related data, memory means for storing instructions and/ordata, commonly utilized for serving as a work area of the processor andthe like, for example, ROM, RAM, EEPROM, and the like, input means,generally for inputting data and/or instructions by software, forexample, a floppy diskette, CD-ROM, EEPROM, data interface means, andthe like, user interface means, typically for providing monitor and/ormanipulation possibilities to a user, for example, a screen, a keyboard,a microphone and headset for communication, and the like, and networkinterface means, commonly for establishing a communication connectionunder the control of the processor unit, for example wired or wirelessinterface means, an antenna, and the like. These means may be integratedwithin one device, for example, in a mobile or fixed telephone or inseveral devices forming the user equipment, for example, in a laptop.

[0048] The network node generally used as the transition mechanismproxy, such as the GGSN, may be implemented by software and/or byhardware. In any case, for executing its respective functions,correspondingly used devices and/or network elements usually includeseveral means which are highly preferable for control and/orcommunication functionality. Such means typically include, for example,a processor unit for executing instructions and/or processing data, forexample, transmission content and signaling related data, memory meansfor storing instructions and data, and commonly for serving as a workarea of the processor and the like, for example, ROM, RAM, EEPROM, andthe like, input means for inputting data and/or instructions bysoftware, for example, a floppy diskette, CD-ROM, EEPROM, and the like,user interface means for providing monitor and/or manipulationpossibilities to a user, for example, a screen, a keyboard and the like,and interface means for establishing a communication connection,typically under the control of the processor unit, for example, wiredand wireless interface means, an antenna, and the like.

[0049] In the following, a first embodiment is described with referenceto FIGS. 1 to 3. This first embodiment is generally directed to a casewhere IPv4 and IPv6 are implemented in the communication network basedon the 3GPP specifications, and the utilized transition mechanism isnormally based on ISATAP.

[0050] In FIG. 1, reference sign 10 denotes a representative userequipment (UE). The UE 10 may be an IPv6 capable terminal device or maybe a dual stack device, implementing both IPv4 and IPv6 stacks.Reference character 20 denotes a Gateway GPRS Support Node (GGSN),commonly representing a control network element of a 2G/3G mobilenetwork 30. The GGSN 20 is typically a dual stack GGSN, implementingboth IPv4 and IPv6 stacks. The 2G/3G mobile network further usuallyincludes access network subsystem elements (not shown), such as basestations and the like, and/or core network subsystem elements, such as aServing GPRS Support Node (SGSN), for establishing and/or controlling acommunication connection to and/or from the UE 10. Reference character100 denotes a IPv4 based operator network. Reference character 40denotes an operator services portion of the operator network 100 whichgenerally includes one or more IPv6 based application servers, thoughonly one is shown in the figure, providing IPv6 based services.Reference character 50 denotes an IP Multimedia Subsystem (IMS) commonlyincluding a Proxy Call State Control Function (P-CSCF), an InterrogatingCall State Control Function (I-CSCF), and/or a Serving Call StateControl Function (S-CSCF). The IPv6 application server and the IMSrepresent two of several possibilities for nodes providing IPv6 serviceswhich the UE 10 may access via the IPv4 operator network. Referencecharacter 60 denotes an edge or border router which is not essential forthe proposed mechanism but that is introduced so as to illustrate thatthe operator network 100 may be connectable to other networks/resourcesthrough corresponding edge and/or border routers.

[0051] In the GGSN 20, the ISATAP functionality, for example,encapsulation/decapsulation, and the like is implemented. However, theISATAP functionality typically is completely transparent to the UE 10.The UE 10 is generally connected to the network, in other words, to theGGSN 20, by using an IPv6 packet based data transmission protocolcontext, in other words, in the present example, by an IPv6 PDP contextbased communication connection 15. Data packets are commonly transmittedvia this connection 15 and an IPv6-in-IPv4 tunneling procedure isnormally performed in the GGSN 10. Thus, corresponding ISATAP links 45,55 typically extend between the IPv6 application services, for example,operator services 40 or IMS 50, and the GGSN 20.

[0052] In the embodiment according to FIG. 1, for example, an IPv6/dualstack UE 10 generally attempts to access an internal IPv6 serviceprovided by the network operator, for example, IMS 50, while theoperator network 100 is commonly still IPv4 based. In other words, themigration to IPv6 is not finalized.

[0053] In FIG. 3, a PDP context activation procedure is illustratedwhich is usually performed by the UE 10, typically in order to establisha communication connection via the mobile network 30 to the desiredservice, for example, IMS 50. The PDP context activation proceduregenerally utilized in the present embodiment is often based on astandard PDP Context Activation Procedure, usually defined in 3GPPspecification TS 23,060, and only those steps of the procedure normallyrelevant to the present example are described in greater detail.

[0054] If no IPv6 PDP context has been previously activated, the UE 10usually requests the activation of a new IPv6 PDP context (step 1) bysending a corresponding request to the network's SGSN, which is notshown in FIG. 1. A PDP address information element is commonly sentaccording to the standard procedure (3GPP TS 23.060) of activating a PDPcontext. When the UE 10 wants to establish an IP connection, it normallyhas to activate a PDP context, and such PDP context is typicallydirectly related to the IP address assigned to the UE. Moreover, whenfollowing the standard procedure to activate a PDP context, the UEgenerally sends an “Activate PDP Context Request” message (3GPP TS23.060) to the SGSN, and such a message commonly includes the PDPaddress information element described below.

[0055] According to certain embodiments, the Activate PDP ContextRequest message sent by the UE 10 specifies a dynamic IPv6 address inthe PDP Address information element. Furthermore, an Access Point Nameinformation element in the request message usually includes the desiredaccess point name (APN) which normally corresponds to the desiredinternal IPv6 service, for example, IMS 50.

[0056] An example of the PDP Address information element according tocertain embodiments is shown in FIG. 2. The PDP Address informationelement of the Activate PDP Context Request message typically includes aplurality of data octets, 1 to N, usually defining respectiveinformation portions of the PDP Address information element. Theseinformation portions normally include a packet data protocol addressinformation element identifier (IEI), a portion defining a length of PDPaddress contents, a portion defining a PDP type organization, a portiondefining a PDP type number, and/or a portion defining addressinformation. Additionally, some portions may be spared by definition.

[0057] For the request of the UE 10 for the activation of a new (IPv6)PDP context in order to access an IPv6 internal service, the content ofthe PDP Address information element of the Activate PDP Context Requestgenerally follows one or more of the rules defined below in order toforce the allocation of a dynamic IPv6 address:

[0058] the value of octet 2 is 0000 0010, indicating dynamic IPaddressing;

[0059] the value of octet 3, a PDP type organization field, is 0001, anIETF allocated address;

[0060] the value of octet 4 is 01010111, an IPv6 address; and

[0061] the address information field remains empty.

[0062] After receiving and validating the Activate PDP Context Requestmessage by the SGSN, a corresponding Create PDP Context Request message(step 2) is typically sent from the SGSN to the affected GGSN 20. TheGGSN 20 may use the included APN to find an external service and/or toactivate a service for the APN.

[0063] Furthermore, an IPv6 address, generally including an IPv6 prefixand an interface identifier, is commonly allocated for the UE 10 by theGGSN (steps 3 to 5). The GGSN 10 normally creates a new entry in aregister typically including a corresponding PDP context table. The newentry generally allows the GGSN 10 to route PDP protocol data units(PDU) between the SGSN and an external PDP network.

[0064] Since the operator network 100 is commonly IPv4 based, atransition mechanism according to ISATAP is also normally executed bythe GGSN 20. Therefore, an ISATAP address is typically highly favorablefor the UE 10. After allocating the IPv6 prefix, an ISATAP formatinterface identifier, in other words, an IPv4 address, is preferablyassigned to the UE 10. However, as the UE 10 may choose to use adifferent interface identifier without involving the network (asspecified, for example, in 3GPP TS 23.060), an allocation of such anISATAP format interface identifier directly to the UE is not generallypreferable. Instead, the GGSN 20 typically keeps the relationshipbetween the PDP context (IPv6) and its corresponding IPv4 address,commonly used for ISATAP, while the PDP context with the UE 10 isactive. The GGSN 20 normally also allocates an IPv4 address, associatesthe IPv4 address with the allocated PDP address, and/or stores (updates)this association in the corresponding entry of the GGSN's PDP contexttable, generally by adding the information element, for example, in a32-bit field, to the table containing the IPv4 address. The 32-bit fieldmay be defined, for example, as a “V4_ISATAP_ADDR” field. In certainembodiments, the GGSN 20 typically includes a pool of, generallyprivate, IPv4 addresses for the allocation. Due to the often huge numberof terminals in a 3GPP network and/or the lack of public IPv4 addresses,it is commonly preferable to allocate private IPv4 addresses for ISATAPsince public addresses are typically not necessary for the tunnelingmechanism.

[0065] In other words, according to certain embodiments, the standardprocedure is generally followed to allocate an interface identifier forthe UE, but when the GGSN 20 creates a new entry in the PDP contexttable to store the assigned IPv6 prefix, it normally also allocates anIPv4 address (ISATAP interface identifier) and commonly stores this inthe new entry of the PDP context table, usually under the“V4_ISATAP_ADDR” field. The allocation of the IPv4 address by the GGSN20 is typically performed by using a pool of IPv4 addresses maintainedin the GGSN 20.

[0066] Then, the GGSN 20 generally returns a Create PDP Context Responsemessage (step 6) to the SGSN, often including the PDP address allocatedby the GGSN 20. The SGSN commonly processes the information included inthe response message, in other words, typically inserting PDP addressesreceived from the GGSN 20, selecting connection resources and the like,and generally sends an Activate PDP context Accept message to the UE 10(step 7) for completing the establishment of the communicationconnection. The above described steps 6 and 7 may be equivalent tocorresponding steps defined in 3GPP TS 23.060.

[0067] Next, other embodiments are described with reference to FIG. 4.Those network elements and processing steps of these embodimentsnormally being equivalent to those of the embodiments described aboveare not described in detail for simplification.

[0068] Some embodiments differ from other embodiments at least withrespect to the allocation process of the IPv4 and IPv6 addresses in theGGSN 20 (steps 3 to 5 in FIG. 4). For example, according to certainembodiments, the GGSN 20 is typically configured, for example, by thenetwork operator to use an external address allocation element forrequesting a respective IP address. The usage of such an externaladdress allocation element may be specified or decided based on the APNindicated in the Activate PDP context Request message (step 1). Theexternal address allocation element may be implemented, for example, bymeans of a Dynamic Host Control Protocol (DHCP) client (not shown),commonly in the GGSN, and a corresponding DHCP server (not shown)generally contacted by the DHCP client.

[0069] As illustrated in FIG. 4, after the SGSN has sent the Create PDPcontext Request message (step 2) to the GGSN 20 and the addressallocation is indicated to be externally controlled, for example, byevaluating the APN, the GGSN 20 usually initially sets the PDP addressfor the UE 10 to 0.0.0.0, and this address is typically returned to theUE 10 via the SGSN. This specific PDP address normally indicates thatthe PDP address may be negotiated by the UE, usually with the externalpacket data network after completion of the PDP Context Activationprocedure. The GGSN is commonly adapted to relay, modify and/or monitorthese negotiations, usually for as long as the PDP context is in anACTIVE state.

[0070] Furthermore, at least with regard to the allocation of the IPv4address for the ISATAP link, the GGSN 20 generally also uses an externaladdress allocation element. Hence, the GGSN 20 typically implements theDHCP client and commonly requests the IPv4 address from a DHCP server(not shown). In addition, the GGSN 20 often keeps the relationshipbetween the PDP context (IPv6) and the corresponding IPv4 address (usedfor ISATAP) while the PDP context with the UE 10 is active. The GGSN 20usually requests an IPv4 address from the external address allocationelement, associates the received IPv4 address with the allocated PDPaddress, and/or stores (updates) this association in the correspondingentry of the GGSN's PDP context table, generally by adding theinformation element, for example, in the 32-bit field “V4_ISATAP_ADDR”,to the table containing the IPv4 address.

[0071] Thus, according to certain embodiments of the present invention,it is often possible to implement a transition mechanism such as, butnot limited to, ISATAP in communication networks, for example, 3GPPbased, in a manner which typically requires no specific changes in theuser terminal nodes. This means, that IPv6-in-IPv4 tunneling is normallycompletely transparent to the (user) terminal nodes. This may beachieved, for example, by defining an ISATAP proxy in the GGSN, whichcommonly performs all of the ISATAP node functionality on behalf of thecorresponding UE. The proposed embodiments may be implemented as asoftware upgrade in the GGSN wherein a new field, for example,“V4_ISATAP_ADDR”, is generally added to the PDP context table, and theGGSN is usually capable of allocating and/or requesting, either from apool of private IPv4 addresses or by using a DHCP client/serverarchitecture, and/or storing a corresponding IPv4 address associatedwith an allocated IPv6 address. The so-called 6in4 tunneling istypically performed by the GGSN using the IPv4 address stored in thecorresponding entry of the PDP context table.

[0072] According to certain embodiments, the allocation of IPv6addresses and IPv4 addresses is commonly performed directly by the GGSN20 while, according to other embodiments, the allocation of IPv6addresses and IPv4 addresses is normally performed by using an externaladdress allocation element such as a DHCP client/server architecture.However, it is also possible to combine these features such that onetype of addresses is generally allocated by the GGSN while the othertype of addresses is typically allocated by the external addressallocation element.

[0073] Moreover, even though certain embodiments of the presentinvention are described as being related to the ISATAP based transitionmechanism and the 3GPP based mobile communication network, it is to beunderstood that the embodiments of the present invention are not limitedto this scenario. For example, certain embodiments may also be appliedfor other communication network types, for example, 3GPP2 based or fixedcommunication networks. Also, the utilized transition mechanism may beof a different type. Certain embodiments are, in general, applicable toany other automatic tunneling mechanism in which it is highly preferablefor tunneling, in other words, encapsulation/decapsulation, to beperformed in the user terminal (UE). For example, certain embodimentsmay be implemented in connection with the so-called Teredo mechanism(UDP tunneling) proposed by C. Huitema et al., and/or the 6over4mechanism proposed by B. Carpenter et al. (see also RFC 2529).

[0074] As described above, a data transmission from a first node, suchas a user equipment UE, to a second node, such as an application serveror IMS, via a communication network using different types ofcommunication protocols, such as a 3GPP communication network using IPv6and IPv4, is typically controlled by means of a transition mechanism,such as ISATAP. The transition mechanism is generally located in thecommunication network, for example, in a gateway node like a GGSN, whichnormally acts as a transition mechanism proxy. A data transmission fromthe first node is often forwarded, and/or tunneled, by the network nodeto the second node, wherein the transition mechanism functionality istypically performed in the network node, usually transparently for thefirst node.

[0075] It should be understood that the above description andaccompanying figures are merely intended to illustrate the presentinvention by way of example only. The described embodiments of thepresent invention may thus vary within the scope of the attached claims.

We claim:
 1. A method of controlling a data transmission from a firstnode to a second node via a communication network wherein the first nodeis connected to the communication network by a communication protocol ofa first type and the communication network uses at least in part acommunication protocol of a second type for forwarding the datatransmission from the first node to the second node, the methodcomprising the steps of: activating a communication connection based onthe communication protocol of the first type from the first node to anetwork node of the communication network; allocating a first connectioninformation part comprising an address related to the communicationprotocol of the first type to the communication connection of the firstnode; allocating, based on a transition mechanism used by thecommunication network, a second connection information part comprisingan address related to the communication protocol of the second type tothe communication connection of the first node; and storing, by thenetwork node, the first connection information part and the secondconnection information part in a register, wherein the second connectioninformation part is associated with the first connection informationpart in a common entry in the register.
 2. The method according to claim1, wherein, in the step of activating the communication connection, anactivation request is sent from the first node to the network node, theactivation request comprising at least one of an indication for adynamic addressing and an indication of an address type for thecommunication protocol of the first type.
 3. The method according toclaim 1, wherein, in the step of allocating the first connectioninformation part comprising an address related to the communicationprotocol of the first type to the communication connection of the firstnode, the address related to the communication protocol of the firsttype is allocated by the network element.
 4. The method according toclaim 1, wherein, in the step of allocating the first connectioninformation part comprising an address related to the communicationprotocol of the first type to the communication connection of the firstnode, the address related to the communication protocol of the firsttype is requested from an external address allocation element contactedby the network element.
 5. The method according to claim 1, wherein, inthe step of allocating the second connection information part comprisingan address related to the communication protocol of the second type tothe communication connection of the first node, the address related tothe communication protocol of the second type is allocated by thenetwork element from an internal pool of addresses.
 6. The methodaccording to claim 1, wherein, in the step of allocating the secondconnection information part comprising an address related to thecommunication protocol of the second type to the communicationconnection of the first node, the address related to the communicationprotocol of the second type is requested from an external addressallocation element contacted by the network element.
 7. The methodaccording to claim 1, wherein, in the storing step, the network elementstores the first connection information part and the second connectioninformation part associated with each other by an entry in a tableportion related to the communication connection of first node, whereinthe second connection information part is stored in a specific tablefield of the table portion.
 8. The method according to claim 1, furthercomprising a step of tunneling, via the network node, the datatransmission based on the communication protocol of the first typebetween the first node and the second node by means of a connectionbased on the communication protocol of the second type.
 9. The methodaccording to claim 1, wherein, in the activating step, the datatransmission comprises a packet based data transmission, thecommunication protocol of the first type comprises one type of anInternet protocol, in particular an IPv6 based protocol, and thecommunication protocol of the second type comprises another type of anInternet protocol, in particular an IPv4 based protocol.
 10. The methodaccording to claim 1, wherein, in the activating step, the communicationconnection between the first node and the network node is based on apacket based data transmission protocol context, in particular on aPacket Data Protocol context.
 11. The method according to claim 1,wherein, in the allocating, based on the transition mechanism step, thetransition mechanism used by the communication network comprises anautomatic tunneling mechanism which uses in particular the Intra-SiteAutomatic Tunnel Addressing Protocol.
 12. The method according to claim1, wherein, in the activating step, the network node comprises a gatewaynode of the communication network, in particular a Gateway GPRS SupportNode.
 13. A system for controlling a data transmission from a first nodeto a second node via a communication network wherein the first node isconnected to the communication network by means of a communicationprotocol of a first type and the communication network uses at least inpart a communication protocol of a second type for forwarding the datatransmission from the first node to the second node, the systemcomprising: means for activating a communication connection based on thecommunication protocol of the first type between the first node and anetwork node of the communication network; means for allocating a firstconnection information part comprising an address related to thecommunication protocol of the first type to the communication connectionof the first node; means for allocating, on the basis of a transitionmechanism used by the communication network, a second connectioninformation part comprising an address related to the communicationprotocol of the second type to the communication connection of the firstnode; and means for associating the second connection information partwith the first connection information part and for storing theassociated first and second connection information parts in a register.14. The system according to claim 13, wherein the means for activatingthe communication connection comprises means for sending and receivingan activation request from the first node to the network node, theactivation request comprising at least one of an indication for adynamic addressing and an indication of an address type for thecommunication protocol of the first type.
 15. The system according toclaim 13, wherein the means for allocating the first connectioninformation part comprises part of the network node wherein the addressrelated to the communication protocol of the first type is allocated bythe network element.
 16. The system according to claim 13, wherein themeans for allocating the first connection information part comprisespart of the network node wherein the address related to thecommunication protocol of the first type is requested from an externaladdress allocation element contacted by the network element.
 17. Thesystem according to claim 13, wherein the means for allocating thesecond connection information part comprises part of the network nodewherein the address related to the communication protocol of the secondtype is allocated by the network element and selected from an internalpool of addresses.
 18. The system according to claim 13, wherein themeans for allocating the second connection information part comprisespart of the network node wherein the address related to thecommunication protocol of the second type is requested from an externaladdress allocation element contacted by the network element.
 19. Thesystem according to claim 13, wherein the means for storing stores theassociated first and second connection information parts in a registerof the network element by updating an entry in a table portion relatedto the communication connection of first node, wherein the secondconnection information part is stored in a specific table field of thetable portion.
 20. The system according to claim 13, wherein the datatransmission based on the communication protocol of the first type istunneled between the first node and the second node by the network nodeby means of a connection based on the communication protocol of thesecond type.
 21. The system according to claim 13, wherein the datatransmission comprises a packet based data transmission, thecommunication protocol of the first type comprises one type of anInternet protocol, in particular an IPv6 based protocol, and thecommunication protocol of the second type comprises another type of anInternet protocol, in particular an IPv4 based protocol.
 22. The systemaccording to claim 13, wherein the communication connection between thefirst node and the network node is based on a packet based datatransmission protocol context, in particular on a Packet Data Protocolcontext.
 23. The system according to claim 13, wherein the transitionmechanism used by the communication network comprises an automatictunneling mechanism which uses in particular the Intra-Site AutomaticTunnel Addressing Protocol.
 24. The system according to claim 13,wherein the network node comprises a gateway node of the communicationnetwork, in particular a Gateway GPRS Support Node.
 25. A network nodeof a communication network, the network node being usable forcontrolling a data transmission from a first node to a second node viathe communication network wherein the first node is connected to thenetwork node by means of a communication protocol of a first type andthe communication network uses at least in part a communication protocolof a second type for forwarding the data transmission from the firstnode to the second node, the network node comprising: means foractivating a communication connection based on the communicationprotocol of the first type between the first node and the network node;means for allocating a first connection information part comprising anaddress related to the communication protocol of the first type to thecommunication connection of the first node; means for allocating, on thebasis of a transition mechanism used by the communication network, asecond connection information part comprising an address related to thecommunication protocol of the second type to the communicationconnection of the first node; and means for associating the secondconnection information part with the first connection information partand for storing the associated first and second connection informationparts in a register.
 26. The network node according to claim 25, whereinthe means for activating the communication connection comprises meansfor receiving an activation request from the first node, the activationrequest comprising at least one of an indication for a dynamicaddressing and an indication of an address type for the communicationprotocol of the first type.
 27. The network node according to claim 25,wherein the means for allocating the first connection information partcomprises addresses related to the communication protocol of the firsttype and allocates a selected one of the addresses.
 28. The network nodeaccording to claim 25, wherein the means for allocating the firstconnection information part requests an address for the address relatedto the communication protocol of the first type from an external addressallocation element.
 29. The network node according to claim 25, whereinthe means for allocating the second connection information partcomprises a pool of addresses related to the communication protocol ofthe second type and allocates a selected one of the addresses.
 30. Thenetwork node according to claim 25, wherein the means for allocating thesecond connection information part requests an address for the addressrelated to the communication protocol of the second type from anexternal address allocation element.
 31. The network element accordingto claim 25, wherein the means for storing stores the associated firstand second connection information parts in a register of the networkelement by updating an entry in a table portion related to thecommunication connection of first node, wherein the second connectioninformation part is stored in a specific table field of the tableportion.
 32. The network node according to claim 25, wherein the networknodes tunnels the data transmission based on the communication protocolof the first type between the first node and the second node by means ofa connection based on the communication protocol of the second type. 33.The network node according to claim 25, wherein the data transmissioncomprises a packet based data transmission, the communication protocolof the first type comprises one type of an Internet protocol, inparticular an IPv6 based protocol, and the communication protocol of thesecond type comprises another type of an Internet protocol, inparticular an IPv4 based protocol.
 34. The network node according toclaim 25, wherein the communication connection between the first nodeand the network node is based on a packet based data transmissionprotocol context, in particular on a Packet Data Protocol context. 35.The network node according to claim 25, wherein the transition mechanismused by the communication network comprises an automatic tunnelingmechanism which uses in particular the Intra-Site Automatic TunnelAddressing Protocol.
 36. The network node according to claim 25, whereinthe network node comprises a gateway node of the communication network,in particular a Gateway GPRS Support Node.
 37. A system for controllinga data transmission from a first node to a second node via acommunication network wherein the first node is connected to thecommunication network by a communication protocol of a first type andthe communication network uses at least in part a communication protocolof a second type for forwarding the data transmission from the firstnode to the second node, the system comprising: an actuator foractivating a communication connection based on the communicationprotocol of the first type between the first node and a network node ofthe communication network; a first node for allocating a firstconnection information part comprising an address related to thecommunication protocol of the first type to the communication connectionof the first node; a second node for allocating, on the basis of atransition mechanism used by the communication network, a secondconnection information part comprising an address related to thecommunication protocol of the second type to the communicationconnection of the first node; and a third node for associating thesecond connection information part with the first connection informationpart and for storing the associated first and second connectioninformation parts in a register.
 38. A network node of a communicationnetwork, the network node being usable for controlling a datatransmission from a first node to a second node via the communicationnetwork wherein the first node is connected to the network node by acommunication protocol of a first type and the communication networkuses at least in part a communication protocol of a second type forforwarding the data transmission from the first node to the second node,the network node comprising: an actuator for activating a communicationconnection based on the communication protocol of the first type betweenthe first node and the network node; a first node for allocating a firstconnection information part comprising an address related to thecommunication protocol of the first type to the communication connectionof the first node; a second node for allocating, on the basis of atransition mechanism used by the communication network, a secondconnection information part comprising an address related to thecommunication protocol of the second type to the communicationconnection of the first node; and a third node for associating thesecond connection information part with the first connection informationpart and for storing the associated first and second connectioninformation parts in a register.